Hypoallergenic milk products and process of making

ABSTRACT

A hypoallergenic milk which has the flavor and smell of natural whole mammalian milk is disclosed herein. The hypoallergenic milk is made from the ultrafiltered permeate of cow&#39;s milk, whey , or other milk fraction. The permeate is substantially free of cow&#39;s milk protein and fat. The hypoallergenic milk product includes a polypeptide, an amino acid, or a combination of both as an additive. The permeate is supplemented with hypoallergenic protein, and optionally fat, vitamins and minerals to meet the minimum daily nutritional requirements for milk.

This is a continuation of copending application Ser. No. 07/562,777,filed on Aug. 3, 1990, now U.S. Pat. No. 5,064,674 which is acontinuation in part of application Ser. No. 297,451, filed Jan. 13,1989, and now U.S. Pat. No. 4,954,361.

FIELD OF THE INVENTION

A hypoallergenic milk made from the permeate of mammalian milk (i.e. theprotein and fat-free component of cow's milk) is disclosed herein. Thehypoallergenic milk has the flavor and smell of whole natural milk, butlacks the component which causes allergic reactions. The hypoallergenicmilk has the favorable features of mother's milk, but lacks foreignanimal protein, and therefore may thus be regarded as "humanized" cow'smilk.

BACKGROUND OF THE INVENTION

Many persons suffer from various allergies, many of which are caused byingesting food containing allergens.

Although the biochemistry of allergic reactions is not preciselyunderstood, it is believed that the allergens cause, upon ingestion orother contact with the body, a specific reagin (or skin sensitizingantibody) to be formed in the bloodstream. The ability to producereagins, chemically identified as IgE, in response to a given allergenis thought to be an inherited characteristic that differentiates anallergic person from a non-allergic person. The specificity of theallergen-reagin reaction and its dependence on molecular configurationof the allergen and reagin is similar to the antigen-antibody reaction.The degree of sensitization is dependent upon the extent of exposure toor ingestion of the allergen. In this respect, the allergen molecule,which is often a protein, may be regarded as a "key" which exactly fitsthe corresponding structural shape of the reagin molecule which may belikened to a "lock". When the key is inserted into the lock, an allergicreaction results.

Different materials contain different allergens. Not all persons mayhave the reagin with which a particular allergen can react. Therefore,some persons are not allergic to particular materials. However, when aparticular reagin reacts with a specific allergen, an allergic reactionresults in any number or type of symptoms. Allergic reactions range fromvery mild symptoms to death. For example, symptoms, both mild andsevere, include skin rashes (allergic eczema and urticaria), dermalsymptoms, respiratory symptoms (including allergic rhinitis andbronchial asthma), gastrointestinal symptoms, and migraine. Violentillnesses have been known to include shock-like reactions, vascularcollapse and allergic anaphylaxis.

Many allergists have recognized that milk contains proteins which areallergens. The allergens of cow's milk frequently cause the formation ofreagins (IgE) in many persons. Thus, many persons, including both adultsand children, are allergic to cow's milk.

Milk is very frequently used in popular food products. It is used notonly in cooking and baking, but it is included in hidden ways as well.For example, casein, caseinate milk solids, whey, whey solids, andlactalbumin are milk products which are components of cookies, cheeses,chocolate (in the form of milk chocolate), ice cream, butter and may beused as flavoring for other food products, such as breakfast cereals,hot and cold beverages, and desserts. These products can also be foundin gravies, breading, whole, dry or evaporated milk, yogurt, sherbet,breads, waffles, creamed vegetables, mashed potatoes, pudding, creameror any diverse products such as hot dogs or spaghetti.

Milk products, which are marketed today as hypoallergenic milk, areneither uniformly hypoallergenic to all patients, nor made from cow'smilk. For example, heat I0 processed milk, in which albumin isdenatured, is of modest benefit to only a limited number of patients. Ahypoallergenic vegetable soybean milk formulation devised in China hasan objectionable smell and after taste. Hypoallergenic milk produced bythe acid process which imitates the stomach's digestive process byutilizing hydrochloric acid to break up proteins, e.g. casein, has anobjectionable smell and taste.

Accordingly, there is a need for a hypoallergenic milk which also hasthe taste and smell of cow's milk.

U.S. Pat. No. 4,293,571 discloses a process for the purification ofpurified protein hydrolysate. In this process, an aqueous solution ofprotein is subjected to hydrolysis, then is heat treated to denature theprotein. The heat-treated material is then ultrafiltered to eliminateprotein.

U.S. Pat. No. 4,402,938 discloses a food and method for making the samefrom colostrum and milk. In this process, the udder of an ungulate isstimulated with an antigen-like material so that the food factor of thewhey is enhanced. The enhanced milk is subsequently ultrafiltered. Theretentate is discarded and the permeate is saved. Preservatives areadded to the milk/colostrum prior to ultrafiltration.

SUMMARY OF THE INVENTION

A hypoallergenic milk product is provided comprising a permeatesubstantially free of hyperallergenic protein prepared by filtration ofmilk or whey through a filtration membrane which will only allowmolecules having a molecular weight of less than or equal to about 5 kDato pass therethrough, the permeate having been prepared without chemicaltreatment to denature or hydrolyze the protein contained therein priorto filtration. The milk product further includes an added hypoallergenicprotein component which may advantageously comprise hypoallergenicprotein per se, amino acids, polypeptides having a molecular weight ofnot more than about 1.5 kDa, or a combination thereof.

The hypoallergenic milk product is prepared by the steps of filteringmilk or whey through a filtration membrane. The filtration membrane willonly allow molecules with a molecular weight of less than or equal toabout 5 kDa to pass therethrough. The permeate is thereafter collectedfrom the filtration step and supplemented with the above-described addedhypoallergenic protein component. The permeate may be optionallysupplemented with hypoallergenic fat, vitamins and minerals.

It is an object of this invention to produce a new and usefulhypoallergenic food product from mammalian milk or whey, and from cow'smilk in particular.

It is another object of this invention to obtain the good taste ofnatural whole or skim milk.

It is an object of the invention to provide a hypoallergenic milkproduct which retains the nutritional content of natural milk.

It is an object of the invention to provide a hypoallergenic milkproduct which may serve as a vehicle for delivery of specializednutritional products.

DETAILED DESCRIPTION OF THE INVENTION

The hypoallergenic milk disclosed hereinafter is formulated upon thefact that protein contained in natural milk is the source of allergensthat react with reagins to produce allergic reactions. Similar to theantigen-antibody reaction, it is believed that the allergen molecules incow's milk, which usually are proteins, have a specific structure whichacts as a "key", while the reagins have a corresponding structure whichacts as a "lock". While this is the theory upon which the hypoallergenicmilk is based, this theory is not meant to be limiting upon theembodiments disclosed hereinafter.

Mammalian milk or whey, such as milk or whey from e.g., cows, sheep orgoats, is filtered through an ultrafiltration membrane or filter toremove all hypoallergenic components. The milk is not pretreated by heatdenaturation or chemical treatment, e.g., acid or enzyme hydrolysis,prior to ultrafiltration. By "chemical treatment" is meant all forms oftreatment of the milk or whey with chemicals other than standard dairyplant rennin treatment directed merely to neutralizing the colloidalparticle charge on casein micelles. Such treatment of the milk resultsin the formation of insoluble casein which may be physically removed, asin the preparation of casein-free sweet whey from whole milk. I havefound that such treatments, directed merely to physical removal ofcasein by centrifugation or filtration, do not adversely affect thetaste of the resulting product, unlike chemical treatments such as acidhydrolysis or acid denaturation of protein, and unlike heat denaturationof protein. Casein-free sweet whey may thus be effectively utilized as asubstitute for whole or skim milk in the production of my hypoallergenicmilk product.

By "milk" as used herein is meant not only whole or skim milk, but anycrudely-filtered preparation thereof, such as, but not limited to, whey.By "whole milk" is meant milk as substantially obtained from the animal.By "skim milk" is meant whole milk less all or part of the fat contenttherein. It therefore may be appreciated that "skim milk" includes suchvariants as "low fat milk" wherein less than substantially all of thefat content has been removed. By "whey" is meant herein the milkcomponent remaining after all or a substantial portion of the fat andcasein contained are removed, or any fraction or variant of whey, suchas, for example, sweet whey permeate (i.e., permeate of whey prepared bycrude filtration), dried sweet whey, demineralized whey, partiallydemineralized whey, delactose whey (i.e., whey from which lactose hasbeen removed), whey protein concentrate, and the like.

Sweet whey permeate is particularly useful as a starting material forthe practice of the invention. It is a by-product of the cheesemanufacturing process. It is typically discarded, used as an animal feedor further processed to obtain lactose. The present invention providesan alternative use for sweet whey permeate.

According to one embodiment, an ultrafiltration membrane is sized toprevent the passage of any substance with a molecular weight greaterthan 5 kDa. Such excluded substances include, but are not limited to:milk protein; viable or non-viable bacteria; bacterial protein antigen;and milk fat. Alternately, ultrafiltration membranes which prevent thepassage of any substance with a molecular weight greater than 1 or 2 kDamay also be used. Ultrafiltration membranes capable of preventing thepassage of 1 or 2 kDa molecular weight substances have proportionatelysmaller pore sizes.

The following milk proteins are trapped by the ultrafiltration membrane(molecular weights are noted in parenthesis): alpha lactalbumin (14kDa); kappa casein (23 kDa); alpha S-1 casein; alpha S-2 casein; betacasein (24 kDa); beta lactoglobulin (37 kDa); bovine serum albumin (65kDa); and immunoglobulins (>100 kDa). These milk proteins are consideredallergenic. Beta lactoglobulin is a dimer at pH 6.6.

It has been found that decreasing the sizing of the filter decreases therelative amount of three milk proteins--alpha lactalbumin, betalactoglobulin and bovine serum albumin--remaining in the permeate. Thus,where 0.27, 0.33 and 0.01 units of these proteins, respectively, arefound in permeates prepared with a 10 kDa membrane (i.e., a filtermembrane which excludes molecules having a molecular weight greater than10 kDa), permeates prepared with 5 kDa dalton filters contain 0.03, 0.03and 0.01 units of these same proteins, respectively. A dialysate,prepared using a 3.5 kDa dialysis membrane, contains less than 0.01units of each of these protein species, resulting in a protein-freedialysate, based upon the limits of the electrophoretic method employedto analyze for protein.

Ultrafiltration membranes having a 3.5 kDa or less molecular weightcut-off are preferred. Polyether sulfone membranes having a 1 kDa or 2kDa cut-off are available, for example, from Advanced MembraneTechnology, San Diego, CA and Dow Denmark, Naskov, Denmark,respectively. Ultrafiltration membranes made of ceramic materials mayalso be used.

Ceramic filters have an advantage over synthetic filters. Ceramicfilters can be sterilized with live steam so that the chemical agents,such as chlorine, do not have to be used to sterilize the filter.Synthetic filters, on the other hand, cannot be sterilized with livesteam, but instead they must be sterilized with chemical agents, forexample, a solution of 200 p.p.m chlorine solution may be used todisinfect the membrane. If a chemical agent is used to disinfect themembrane, the chemical agent may be washed from the filter by flushingthe filter with two passes of milk.

A pressure gradient is preferably applied across the ultrafiltrationmembrane to facilitate filtration. Preferably, the pressure gradient isadjusted to maintain a filter flux of about 24 liters/m² -hour, which isthe typical dairy plant filter flux. The filter is advantageously firstprimed with a small amount of milk and the permeate discarded, prior tobeginning filtration. Priming of the filter in this manner is believedto be advantageous to filtering efficiency.

The pH of the milk during filtration should be within the range of about2 to about 11. The preferred pH is about 6.6. The pH of sweetcasein-free whey is typically about 6.1.

The temperature of the milk during ultrafiltration should be within therange of about 40° F. to about 150° F.

Instead of ultrafiltration, the allergenic component of the milk or wheymay be removed by dialysis. As is well known, dialysis operates on aprincipal akin to osmosis. The allergenic protein in the permeate iseffectively trapped utilizing a 5 kDa, (preferably a 3.5 kDa, 2 kDa or 1kDa) ultrafilter or dialysis membrane.

With dialysis, as with ultrafiltration, the permeate that passes throughthe membrane, i.e. the hypoallergenic component, is saved and utilized.The retentate, i.e., the material which does not pass through themembrane, is discarded or utilized in other commercial applications. Adialysis membrane capable of preventing the passage of materials with amolecular weight of 5 kDa may be used. Other membranes, however, couldbe used so long as the hyperallergenic component is excluded from thepermeate.

The permeate collected from the ultrafiltration process is free of fat,milk protein, bacteria and bacterial protein antigen. The permeatecontains, among other things: riboflavin (the substance which gives thepermeate a yellow color); lactose (less than 5% by weight); salt or ashcontaining calcium; C₇ -C₁₀ carbon compounds, particular theseven-carbon compound cis-4-heptanal, which is an unsaturated aldehyde;dimethyl sulfide; and other minerals typically found in pasteurizedmilk. These materials, as well as milk fat subsequently re-added (afterdeproteinization), give the enriched permeate the good taste and smellof whole milk. The retentate is of no further use in the hypoallergenicmilk manufacturing process, and may be discarded or used in otherprocesses beyond the scope of the invention, for example in themanufacture of ice cream.

The permeate which is deproteinized and defatted may be supplementedwith hypoallergenic protein, fat, vitamins, minerals and flavoring sothat it meets the minimum daily requirement (M.D.R.) for milk.Preservatives such as phenol, parabens etc. are preferably not added.The permeate may be supplemented, as discussed below, while in liquidform. Alternatively or additionally, it may be freeze dried in anyconventional manner, then reconstituted with liquid supplements at alater time.

The supplements include, among other things, a hypoallergenic proteincomponent, hypoallergenic fat, vitamins, minerals and flavoring, such asnatural vanilla flavoring. The hypoallergenic protein component maycomprise hypoallergenic protein per se, such as protein from cereal orvegetable sources. Alternatively, or additionally, it may comprise freeamino acids, or polypeptides of animal source, provided the polypeptidesare not larger than about 1.5 kDa, preferably not larger than about 1kDa.

Sources of hypoallergenic protein include, but are not limited to: oatcereal (which has a high protein level of about 18%); rice cereal;barley cereal; or any other food source having a low allergenicity andample protein content. Vegetable sources of protein may also be used, solong as they have a low allergenic potential. Vegetable sources of lowallergenic protein include, for example, potato and soy isolate.Combinations of the foregoing proteins may also be used.

Oat cereal, for example oatmeal, is preferred because it not onlyenhances the protein content, it also adds to the taste of the resultingproduct. The oat cereal is used as a very finely ground flour, tofacilitate dissolution into the permeate. About 5 to 10 grams of thevery finely ground and sieved cereal flour is added to about 100 cc ofpermeate. The resulting mixture has a protein content of about 0.9 to1.8% by weight, which is similar to human breast milk.

When cereals are used, protein soy isolate may also be added to enrichthe lysine amino acid value of the cereal. Additionally, the protein maybe supplemented with, among other things, methionine, cystine, andiodine to meet the minimum daily requirements (M.D.R.).

Protein soy isolate is preferred for use in hypoallergenic milk which isintended for infants, who require a single source of protein, orchildren and adolescents with important growth factor requirements.Cereal hypoallergenic protein sources can be used in the hypoallergenicmilk for adults. For example, if a multiple source of protein isdesired, any combination of hypoallergenic protein sources may be used.

In lieu of, or in addition to, supplementation with hypoallergenicprotein, the permeate may be supplemented with amino acids, short chainpolypeptides, or a combination of amino acids and short chainpolypeptides. By "short chain polypeptide" is meant a polypeptide havinga molecular weight of no more than about 1.5 kDa, preferably not morethan about kDa. Free amino acids and short chain polypeptides arehypoallergenic regardless of source, and therefore will not contributeto the allergenicity of the milk product. Preferably, the amino acidscomprise a mixture of amino acids, most preferably a mixture containingat least the nine amino acids which are essential to the human diet:

    ______________________________________                                        Threonine     Valine       Phenylalanine                                      Methionine    Isoleucine   Histidine                                          Lysine        Leucine      Tryptophan                                         ______________________________________                                    

The short chain polypeptides may comprise individual polypeptides or amixture of polypeptides. The short chain polypeptides and amino acidsmay be obtained by appropriate hydrolysis of any suitable polypeptidesor proteins. Preferably, they are obtained from milk proteins, so thatthe reconstituted hypoallergenic milk product of the invention maintainsa portion of the protein nutritional content of whole milk. Hydrolysatesof milk proteins are commercially available. For example, a series ofhydrolysates are produced by Deltown Chemurgic Corporation, Fraser, NewYork, under the trademark "DELLAC". "DELLAC" CE80PS is a highlyhydrolyzed pancreatic digest of casein. "DELLAC" LE80PS is a hydrolyzedpancreatic digest of another milk protein, lactalbumin. High-performanceliquid chromatography indicates that these products are free ofpolypeptides having a molecular weight of greater than about 1.5 kDa.Hydrolysates of non-milk proteins may also be employed, e.g. "DELLAC"SE50M, which is a papaic digest of soy flour.

Each of the aforementioned products may be advantageously utilized inthe practice of the invention since they are either free of allergenicmilk protein, or are at least free of any milk-derived polypeptideslarge enough to be considered allergenic.

While it is preferred that the short chain polypeptides and amino acidsare added to the permeate after filtration, it is possible that they maybe added to the milk or whey prior to filtration. In such cases, it maythen be feasible to utilize as a source of short chain polypeptides milkprotein hydrolysate which may include some polypeptide species largeenough to be considered hyperallergenic, since these larger species willbe removed by the filtration step. One example of such a milk proteinhydrosylate is "DELLAC" LE80GF, an enzymatic digest of lactalbumin. Itconsists of 80% by weight protein-derived materials, of which 97 wt. %comprises short chain polypeptide and 3 wt. % whole protein. The producthas an average molecular weight to about 2 kDa.

Hydrolysates of lactalbumin are particularly preferred for supplyingshort chain polypeptides and/or amino acids in the practice of thepresent invention. Lactalbumin and its hydrolysates contain a relativesurplus of the four essential amino acids lysine, methioning, threonineand isoleucine. It can, therefore, be an important supplement to cerealor vegetable protein which is somewhat deficient in these amino acids.Lactalbumin hydrolysates are particularly useful when combined withother protein sources, such as soy isolate or casein hydrolysate, whichmay be somewhat deficient in the amino acids cystine and methionine.

It should be noted that while the aforementioned refinedpolypeptide-containing products result from enzyme hydrolysis of singlemilk proteins, their addition to the permeate prepared according to thepresent invention does not significantly impact on the taste of thefinal reconstituted hypoallergenic milk product. This should becontrasted with the situation where whole milk, before filtration, istreated in situ with hydrolytic enzymes. This form of in situ hydrolysisof milk proteins deleteriously impacts on the taste of the resultingproduct.

The sources of fat (or lipids) may include deproteinized clear butterand butter oil or butter fat, polyunsaturated and mono- and/orpolyunsaturated vegetable oil or fat from milk free margarine sources,sesame, safflower, and the like. The foregoing fats are hypoallergenic.

The fat is optionally added to the permeate so that the fat content ofthe resulting mixture ranges between 0% and about 4% by weight dependingupon whether skim, 1%, 2% or 4% homogenized milk is desired. For adultswhere atherosclerosis prevention is of great importance, the fat sourcemay comprise about 1/4 to about 1/2% deproteinized butter oil and/orabout 1/2 to about 2% low fat polyunsaturated vegetable fat.

Deproteinized hypoallergenic butter for supplementing the permeate maybe made from commercially available salt-free, sweet 99.99% anhydrousmilk fat. The milk fat is melted in boiling water. The resulting butteroil is then removed from the boiling water, such as by pipetting it offthe surface of the water. The process removes, by dilution and washingof the milk fat with water, any protein which may be contained in thefat as a contaminant. The process may be repeated any number of times toensure the purity of the resulting butter product.

Vitamins and minerals are also optionally added to the protein- andfat-supplemented permeate. Vitamins and minerals are added to thereconstituted, modified hypoallergenic milk so that the milk meets theminimum daily requirement. By way of non-limiting example, the followingmay be added, based upon one quart of permeate supplemented withhypoallergenic protein and fat: 400 micrograms of water dispersibleVitamin D; 2100 micrograms of water-dispersible Vitamin A; 60 milligramsof Vitamin C acetate; folic acid; calcium pantothenate; biotin;pyridoxine; minerals such as calcium triphosphate, iron as ferroussulfate, and zinc as zinc sulfate. The foregoing are exemplary of thevitamins and minerals that may be added to the hypoallergenic milk. Ofcourse, other vitamins and minerals which are known to those of ordinaryskill in the art may also be added.

Additives to enhance the flavor and consistency of the hypoallergenicmilk may also be added. Exemplary additives include: hypoallergenic beangum derived from guar gum (3 to 4 pounds per 1,000 gals. ofhypoallergenic milk); carrageenan; and/or lecithin of hypoallergenicvegetable bean source, such as soy bean (20 lbs/1000 gallons ofhypoallergenic milk). Each of these additives impart a creamyconsistency (acts as an emulsifier) to the hypoallergenic milk. Naturalvanilla may also be added to enhance the flavor of hypoallergenic milk.

After the hypoallergenic protein component and optional fats, vitamins,minerals and additives to enhance flavor and consistency have been addedto the permeate, the hypoallergenic milk is preferably blended in anemulsifying and diffusing apparatus operating at between about 2,500 andabout 3,500 r.p.m., to ensure thorough mixing. The blendedhypoallergenic milk is then homogenized at a pressure ranging from about2,000 to about 4,000 P.S.I., pasteurized at about 170° F. for about 30minutes, and then flashed sterilized at about 290° F. for about 12seconds and packaged into a aseptic containers. Such containers are madeof materials which will not leach into the packaged product. Thematerials include, but are not limited to, glass, waxed cardboard ormetal. Alternatively, the permeate may be pasteurized before the varioussupplements have been added.

The meticulous removal of substantially all allergenic protein by anultrafilter or dialysis membrane has superior advantage regardinghypoallergenicity. The permeate is deproteinized as evidenced by theabsence of protein bands upon SDS-PAGE, sensitive to the application of30 nanograms/microliter or greater concentration of protein. Thus, it isunderstood that as used herein, the expression "substantially completelydeproteinized" or "substantially free of milk protein" in referring to amilk preparation, means a preparation free of protein bands uponSDS-PAGE sensitive to the presence of protein concentrations of 30nanograms/microliter or higher.

Lactase enzyme may be added to the hypoallergenic milk for use by anolder child or adult where lactose intolerance may be a consideration.

The hypoallergenic milk may be substituted for milk in any formulationin which milk is used. For example, hypoallergenic milk may be used as abeverage or in beverages, or solid food products such as candy, milkchocolate, cookies, cakes, breakfast cereals and the like. Thehypoallergenic milk product may also be utilized as a vehicle for thedelivery of specialized nutritional products, which might otherwise havean objectionable taste to the patient. Thus, use of the hypoallergenicmilk product as a vehicle for offensive-tasting enteral products mayobviate the need for introducing such products by stomach tube, whichoccurs in patients suffering from such diseases as ileitis, colitis, andgeriatric nursing home patients.

One non-limiting hypoallergenic milk product according to the presentinvention suitable for infants contains the following components, basedupon 100 ml of product. The amount of each component may be adjustedaccording to need.

    ______________________________________                                        Protein                                                                       Soy protein isolate                                                                              1.8 g                                                      Oatmeal protein (optional)                                                                       0.9 to 1.8 g                                               Fat                3.7 g                                                      Carbohydrate                                                                  Lactose            4.6 g                                                      Minerals                                                                      Sodium             41 to 49 mg                                                Potassium          140 to 152 mg                                              Calcium            110 to 119 mg                                              Phosphorus         89 to 93 mg                                                Chloride           63 to 65 mg                                                Iron (fortified)   0.05 to 1.2 mg                                             Zinc               0.38 to 0.43 mg                                            Iodine             10 micrograms                                              Amino Acids                                                                   Methionine         10 micrograms                                              Cystine            10 micrograms                                              Vitamins                                                                      Vitamin A          210 International Units                                    (water dispersible)                                                                              ("I.U.")                                                   Vitamin C          6.0 mg                                                     (as acetate)                                                                  Vitamin D          42 I.U.                                                    (water dispersible)                                                           Vitamin E          1.0 mg                                                     Thiamine           0.04 mg                                                    Riboflavin         0.14 to 0.16 mg                                            Niacin             0.08 mg                                                    Pyridoxine         0.04 to 0.05 mg                                            Vitamin B.sub.12   0.32 micrograms                                            Folic Acid         5.0 micrograms                                             ______________________________________                                    

According to another embodiment, a hypoallergenic milk product suitablefor infants has the foregoing components, except that eh soy proteinisolate, methione and cystine are omitted in favor of a mixture of freeamino acids, comprising preferably at least all the essential aminoacids, or, alternatively a mixture of short chain polypeptides.Preferably, the infant formula utilizes a mixture of short chainpolypeptides derived from milk protein, such as any of the availablehydrolysates of milk proteins described above.

The method of the invention is effective in reducing the protein contentof milk from 3.6% to 0.26%, a reduction of more than 90%. It should benoted that by utilizing a filter capable of retaining 5 kDa molecularweight species, 90% more protein is removed from the permeate than witha 10 kDa filter. A filter capable of retaining 3.5 kDa molecular weightspecies results in the complete absence of protein, as evidenced bySDS-PAGE.

The treatment of the invention effectively removes all casein, and allthe other milk proteins, and all immunoglobulins. The trace amounts ofthe other proteins remaining in the permeate are heat denatured by thepasteurization process utilized above.

The invention will now be described in more detail with reference to thefollowing specific, non-limiting examples:

EXAMPLE 1

Whole cow's milk was passed through an ultrafiltration membrane("A.E.S.-1", Advanced Membrane Technology, San Diego, CA) having a 1 kDamolecular weight cut-off at 40° F. and pH 6.6. Filtration wasfacilitated by applying a pressure gradient of about 5 psi across themembrane. The absence of protein in the permeate was demonstrated by theabsence of protein bands upon sodium dodecyl sulfate polyacrylamide gelelectrophoresis ("SDS-PAGE") and silver staining. The use of a silverstain is generally three times more sensitive for detection of proteinsthan colored stains such as Koomasie Blue. Nine ml of the permeate wasthen supplemented with 203.8 mg "DELLAC" LE80PS (Deltown ChemurgicCorp.), which comprises 80% by weight amino acids and oligopeptides frompancreatic digestion of lactalbumin. "DELLAC" LE80PS has been determinedto be non-allergenic by a guinea pig challenge test. The supplementedpermeate was transferred to a 10 ml screw top test tube and furtherprocessed for 20 minutes by mixing and shaking to produce a homogeneoussolution.

EXAMPLE 2

Nine ml of the permeate prepared according to Example 1 was supplementedwith 301 mg of "DELLAC" CE80GPS, which comprises 80% by weight of aminoacids and oligopeptides resulting from hydrolysis of casein byaminopeptidases extracted from Streptococcus lactis. "DELLAC" CE80GPShas been determined to be non-allergenic by a guinea pig challenge test.The supplemented permeate was then transferred to a 10 ml screw top testtube and further processed for 20 minutes by mixing and shaking toproduce a homogeneous solution.

EXAMPLE 3

9 ml of the permeate prepared according to Example was supplemented with200 mg of. "DELLAC" CE80PS, comprising 80% by weight of amino acids andoligopeptides resulting from the pancreatic digest of casein. It hasbeen determined to be non-allergenic by a guinea pig challenge test.This sample was transferred to a 10 ml screw top test tube and furtherprocessed for 20 minutes by mixing and shaking to produce a homogeneoussolution.

EXAMPLE 4

Nine ml of the permeate prepared according to Example 1 was supplementedwith 302.1 mg of "DELLAC" SE50M, a papiac digest of soy flour comprising50% by weight amino acids and oligopeptides. This sample was transferredto a 10 ml screw top test tube and further processed for 20 minutes bymixing and shaking to produce a homogeneous solution.

EXAMPLE 5

To the supplemented permeate of Example 2 there was further added 0.1 mlof cleared anhydrous butter oil (prepared according to Example 11,below). This sample was transferred to a 10 ml screw top test tube andfurther processed for 20 minutes by mixing and shaking to produce ahomogeneous solution. The absence of protein was demonstrated bySDS-PAGE.

EXAMPLE 6

To the supplemented permeate prepared according to Example 4 there wasadded 0.1 ml of cleared anhydrous butter oil (prepared according toExample 11, below). This sample was transferred to a 10 ml screw toptest tube and further processed for 20 minutes by mixing and shaking toproduce a homogeneous solution.

EXAMPLE 7

Sweet casein-free whey derived from whole cow's milk was passed througha 1 kDa cut-off ultrafiltration membrane ("A.E.S.-1", Advanced MembraneTechnology, San Diego, CA). The milk was maintained at a temperature of5°-10° C. and a pH of 6.1. Filtration was facilitated by applying apressure gradient of about 60-80 psi across the membrane. The absence ofprotein in the permeate was confirmed by SDS-PAGE. 250 ml of thepermeate was then enriched with 3126 mg of "DELLAC" LE80PS. The samplewas processed by shaking and mixing for 20 minutes to produce ahomogeneous mixture.

EXAMPLE 8

125 ml of the enriched permeate of Example 7 was supplemented by adding7.5 grams of a very finely ground and sifted oat soy flour, in the formof commercially available oat soy powder, with constant stirring for 20minutes. The oat flour-enriched permeate was then pasteurized for 20seconds with constant stirring in a double boiler at 72° C. (170° F.),and then further supplemented with 1.25 ml of cleared hypoallergenicanhydrous butter oil (prepared as in Example 11, below). The resultingreconstituted hypoallergenic milk product was decanted into a 4 ouncesterile glass bottle and refrigerated. It was chilled, then homogenizedusing a homogenizer operating at 9000 rpm, and then chilled again. Thegood smell and taste of cow's milk was observed, with an appearancesimilar to skim milk.

EXAMPLE 9

Examples 7 and 8 were repeated, substituting skim milk for sweetcasein-free whey. The pH at which the milk was maintained duringfiltration was increased to 6.6. The resulting hypoallergenic milkproduct displayed the good smell and taste of cow's milk, with anappearance similar to conventional skim milk.

EXAMPLE 10

Fresh whole guernsey cow's milk was collected (7:30 a.m.) and separated(9:30 a.m.) from fat. The skim milk was then brought to 104° F. (40° C.)temperature for separation. The skim milk was then placed in an ice bathto a temperature of 52° F. Fourteen liters of this milk was transferredto a cold room (50° F.). Fourteen liters of this milk was transferred toa cold room (50° F.) and was subjected to constant stirring. The skimmilk was placed in six 90 ml, 3,500 molecular weight dialysis tubes tiedat each end (i.e., species >3.5 kDa do not pass through) and dialyzedagainst deionized, distilled water. The dialysate, which contained 6.1%solids, on chemical analysis revealed 0.27% protein or polypeptides, andother nitrogencontaining compounds by the BCA method, Clinical Chemistry32:120 (1986). Gel electrophoresis of the dialysate, which is sensitiveto the application of 30 ng/microliter protein to the gel, revealed noprotein. It is significant to note that neither casein, nor any of theother milk proteins, were present in the permeate, as established by gelelectrophoresis.

Two hundred and forty ml of this dialysate was then mixed with 25 gramsof an enriched soy solids powder containing hypoallergenic soy oil,lecithin as an emulsifier, and vitamins and minerals.

The addition of the soy powder resulted in a hypoallergenic milkformulation containing about 2% protein (weight/volume) and about 2% fat(weight/volume). Constant stirring for 20 minutes resulted in acolloidal suspension.

The suspension was then pasteurized at 170° F. for 30 minutes in adouble boiler with further constant stirring. This heating in a doubleboiler also serves to heat denature any remote trace of protein. Themilk was then poured into four 8 ounce sterile glass bottles andrefrigerated. The tan colored colloidal suspension was found to bemaintained upon gross inspection at two hours, eight hours, and eighteenhours after preparation.

EXAMPLE 11

A. A hypoallergenic butter product substantially completely free ofhyperallergenic protein may be prepared as follows:

Twenty grams of anhydrous milk fat 99.99% pure (0.01 moisture) iscleared of any possible trace of protein in 5,000 ml of boiling water,rendering a hypoallergenic butter oil. The butter oil is then pipettedoff the water.

B. 0.1 cc of the butter oil was added to 9 ml of the permeate preparedaccording to Example 1. The absence of protein bands was observed uponsubjecting the product to SDS-PAGE.

EXAMPLE 12

Skim milk was first enriched by adding a sufficient quantity of "DELLAC"LE80GF to produce 1.5 wt. % concentration of LE80GF prior toultrafiltration. The enriched milk was passed through an ultrafiltrationmembrane ("A.E.S.-1", Advanced Membrane Technology, San Diego, CA),having a 1 kDa molecular weight cut-off. The milk was maintained at 70°F. and pH 6.6. Filtration was facilitated by applying a pressuregradient of about 350 p.s.i. across the membrane, to obtain a filterflux equal to or in excess of 24 liters per square meter ofultrafiltration membrane, per hour. The formulation was then transferredto screw top containers, and refrigerated.

EXAMPLE 13

Example 12 was repeated substituting an ultrafiltration membrane havinga 2 kDa molecular weight cut-off ("GR90 2K", Dow Denmark, Naskov,Denmark), for the 1 kDa cut-off ultrafiltration membrane used in Example12.

EXAMPLE 14

Example 12 was repeated substituting casein-free sweet whey for skimmilk and decreasing the pH to 6.1 from 6.6. The pressure gradient wasdecreased from 350 p.s.i. to 75 p.s.i. to obtain a filtration flux of 241/m² -hour. The permeate was then transferred to screw top containers.

EXAMPLE 15

Example 15 was repeated, substituting a 2 kDa cut off membrane ("GR902K", Dow Denmark, Naskov, Denmark) for the 1 kDa cut-off filter used inExample 15. The pressure gradient was increased to 350 p.s.i. to achievea dairy plant filtration flux rate of 24 liters/m² -hour.

EXAMPLE 16

A crude permeate of casein-free sweet whey was prepared by passingcasein-free sweet whey through an ultrafiltration membrane ("HFK 131"polyether sulfone 10K, Koch Membrane System, Inc., Wilmington, MA),having a 10K Da molecular weight cut off. The casein-free sweet whey wasmaintained at 70° F. and pH 6.1 Filtration was facilitated by applying apressure gradient of about 40-45 p.s.i. across the membrane. The crudepermeate was enriched by adding a sufficient quantity of "DELLAC" LE80GFto produce a 1.5 wt. % concentration of LE80GF. The enriched crudepermeate was further purified by passage through a 1 kDa cut-offultrafiltration membrane ("A.E.S.-1", Advanced Membrane Technology, SanDiego, CA) at 70° F. and pH 6.1. Filtration was facilitated bymaintaining a pressure gradient of about 75 p.s.i. to provide a filterflux of 24 l/m² -hour. The final ultrafiltered permeate was thentransferred to screw top containers.

EXAMPLE 17

Example 16 was repeated substituting the 2 kDa cutoff ultrafiltrationmembrane ("GR90 2K", Dow Denmark, Naskov, Denmark) for the 1 kDa cut-offultrafiltration used in Example 16. The pressure gradient required wasincreased to 350 p.s.i. The permeate was then transferred to screw topcontainers.

EXAMPLE 18

500 ml of the final ultrafiltered permeate of Example 16 was pasteurizedat 72° C. for 20 minutes. This heating further serves to denature anyremaining trace of protein. The permeate was then supplemented asfollows: 15 grams of finely ground and sifted oat soy powder in the formof commercially available oat soy powder were added to the pasteurizedpermeate, followed by the addition of 2.5 ml of cleared anhydrous butteroil (as prepared in Example 11). The enriched permeate was thenhomogenized using a homogenizer operating at 9000 RPM. The formulationwas then decanted into two 4 ounce glass bottles and refrigerated. Theresulting tan colored suspension was found to be maintained upon grossinspection at two, eight and eighteen hours following preparation. Thegood taste and smell of cow's milk was observed, with an appearancesimilar to skim milk.

The presence of medication utilized to treat milkproducing cows isundesirable in milk for human consumption. The ultra filtration methoddescribed herein is believed to effectively reduce the level ofveterinary pharmaceuticals contained in cow's milk. Approximately 75% ofmonocyclic drugs, e.g., penicillin and sulfonamides, which may bepresent in the milk, are attached to the milk's protein fraction.Approximately 25% or more of tricyclic compounds, and approximately 50%of bicyclic compounds, are similarly found attached to the proteinfraction. Thus, it may be readily appreciated that removal of milkprotein, as in the practice of the present invention, serves also tosubstantially reduce the level of veterinary medications which may becontained in cow's milk.

The present invention may be embodied in other specific forms withoutdeparting from the spirit or essential attributes thereof and,accordingly, reference should be made to the appended claims, ratherthan to the foregoing specification, as indicating the scope of theinvention.

I claim:
 1. A hypoallergenic milk product comprising:(a) a permeatesubstance free of hyperallergenic protein containing molecules thereinhaving a molecular weight of less than or equal to about 5 kDa, saidpermeate being selected from the group consisting of milk permeate andwhey permeate; and (b) a nutritionally effective amount of an additiveselected from the group consisting of short chain polypeptides, aminoacids, and a combination thereof.
 2. A milk product according to claim 1further comprising hypoallergenic fat.
 3. A milk product according toclaim 2 wherein said hypoallergenic fat is selected from the groupconsisting of deproteinized butter, vegetable oil and combinationsthereof.
 4. A process for making a hypoallergenic product comprising thesteps of:(a) supplementing a crude permeate derived from milk or wheywith an added component selected from the group consisting of aminoacids and polypeptides; (b) filtering the supplemented crude permeatethrough a filtration membrane which will only allow molecules with amolecular weight of less than or equal to about 5 kDa to passtherethrough; and (c) collecting said permeate.
 5. A process accordingto claim 4 wherein said crude permeate is prepared by filtration of milkor whey through a filtration membrane which will only allow moleculeswith a molecular weight of less than or equal to about 10 kDa to passtherethrough.
 6. A process according to claim 5 wherein the collectedpermeate is supplemented with hypoallergenic fat.
 7. A process accordingto claim 4 wherein the collected permeate is supplemented withhypoallergenic fat.
 8. A process according to claim 4 wherein thefiltration membrane will only allow molecules with a molecular weight ofless than or equal to about 3.5 kDa to pass therethrough.
 9. A processaccording to claim 8 wherein the filtration membrane will only allowmolecules with a molecular weight of less than or equal to about 2 kDato pass therethrough.
 10. A process according to claim 9 wherein thefiltration membrane will only allow molecules with a molecular weight ofless than or equal to about 1 kDa to pass therethrough.
 11. A process ofmaking a hypoallergenic milk product comprising the steps of:(a)separating milk or whey to isolate molecules thereof having a molecularweight of about 5 kDa or less to produce a permeate; (b) collecting saidpermeate; (c) admixing into said permeate an additive selected from thegroup consisting of amino acids, short chain polypeptides and mixturesthereof to form a supplemented permeate; and (d) adding a hypoallergenicprotein into said supplemented permeate, said hypoallergenic proteinbeing selected from the group consisting of cereal protein, vegetableprotein and combinations thereof.
 12. A process for making a palatablehypoallergenic milk product comprising the steps of:(a) supplementing amilk component with at least one component selected from the groupconsisting of amino acids and polypeptides; (b) filtering thesupplemented milk component through a filtration medium which will allowmolecules with a molecular weight of less than or equal to about 5 kDato pass therethrough; and (c) collecting the permeate from thefiltration step.
 13. A process according to claim 12 wherein thefiltration membrane will only allow molecules having a molecular weightless than or equal to about 3.5 kDa to pass therethrough.
 14. A processaccording to claim 13 wherein the filtration membrane will only allowmolecules having a molecular weight less than or equal to about 2.0 kDato pass therethrough.
 15. A process according to claim 14 wherein thefiltration membrane will only allow molecules having a molecular weightless than or equal to about 1.0 kDa to pass therethrough.
 16. A processaccording to claim 13 wherein the hypoallergenic product issubstantially free of protein of animal origin as determined by thesubstantial absence of protein bands upon sodium dodecyl sulfatepolyacrylamide gel electrophoresis and silver staining.
 17. A processaccording to claim 12 wherein said amino acids or polypeptides or bothare derived from at least one component selected from the groupconsisting of casein, soy flour and lactalbumin.
 18. A palatablehypoallergenic milk product comprising:(a) a permeate substance whereinthe allergenic protein has been removed through ultrafiltration, saidpermeate containing molecules having a molecular weight less than orequal to about 5 kDa, and said permeate being selected from the groupconsisting of milk permeate and whey permeate; and (b) a naturallyeffective amount of an additive selected from the group consisting ofshort-chain polypeptides, amino acids, and a combination thereof.
 19. Amilk product according to claim 18 further comprising hypoallergenicfat.
 20. A milk product according to claim 19 wherein saidhypoallergenic fat is selected from the group consisting ofdeproteinized butter, vegetable oil and combinations thereof.
 21. A milkproduct according to claim 18 wherein said amino acids or polypeptidesor both are derived from at least one component selected from the groupconsisting of casein, soy flour and lactalbumin.
 22. A milk productaccording to claim 18 wherein said permeate substance is prepared bysupplementing a milk component with polypeptides or amino acids, orboth, prior to said ultrafiltration.
 23. A milk product according toclaim 18 wherein said permeate contains molecules having a molecularweight less than or equal to about 3.5 kDa.
 24. A milk product accordingto claim 23 wherein said permeate substance is substantially free ofprotein of animal origin as determined by the substantial absence ofprotein bands upon sodium dodecyl sulfate polyacrylamide gelelectrophoresis and silver staining.
 25. A milk product according toclaim 23 wherein said permeate contains molecules having a molecularweight less than or equal to about 2.0 kDa.
 26. A milk product accordingto claim 25 wherein said permeate contains molecules having a molecularweight less than or equal to about 1.0 kDa.
 27. A palatablehypoallergenic milk product comprising:(a) a permeate substance whereinthe allergenic protein has been removed through ultrafiltration, saidpermeate containing molecules having a molecular weight less than orequal to about 5 kDa, and said permeate being selected from the groupconsisting of milk permeate and whey permeate; (b) a nutritionallyeffective amount of an additive selected from the group consisting ofshort-chain polypeptides, amino acids, and a combination thereof; and(c) a hypoallergenic milk chocolate prepared with hypoallergenic milk.28. A milk product according to claim 27 further comprisinghypoallergenic fat.
 29. A milk product according to claim 28 whereinsaid hypoallergenic fat is selected from the group consisting ofdeproteinized butter, vegetable oil and combinations thereof.
 30. A milkproduct according to claim 27 wherein said amino acids or polypeptides,or both, are derived from at least one component selected from the groupconsisting of casein, soy flour and lactalbumin.
 31. A milk productaccording to claim 27 wherein said permeate substance is prepared bysupplementing a milk component with polypeptides or amino acids, or bothprior to said ultrafiltration.
 32. A milk product according to claim 27wherein said permeate contains molecules having a molecular weight lessthan or equal to about 3.5 kDa.
 33. A milk product according to claim 32wherein said permeate substance is substantially free of protein ofanimal origin as determined by the substantial absence of protein bandsupon sodium dodecyl sulfate polyacrylamide gel electrophoresis andsilver staining.
 34. A milk product according to claim 32 wherein saidpermeate contains molecules having a molecular weight less than or equalto about 2.0 kDa.
 35. A milk product according to claim 34 wherein saidpermeate contains molecules having a molecular weight less than or equalto about 1.0 l kDa.
 36. A palatable hypoallergenic milk productcomprising:(a) a permeate substance substantially free of allergenicprotein, said permeate containing molecules having a molecular weightless than or equal to about 5 kDa, and said permeate being selected fromthe group consisting of milk permeate and whey permeate; and (b) anutritionally effective amount of an additive selected from the groupconsisting of short-chain polypeptides, amino acids, and a combinationthereof.
 37. A milk product according to claim 36 wherein said aminoacids or polypeptides, or both, are derived from at least one componentselected from the group consisting of casein, soy flour and lactalbumin.38. A milk product according to claim 36 wherein said permeate containsmolecules having a molecular weight less than or equal to about 3.5 kDa.39. A milk product according to claim 38 wherein said permeate substanceis substantially free of protein of animal origin as determined by thesubstantial absence of protein bands upon sodium dodecyl sulfatepolyacrylamide gel electrophoresis and silver staining.
 40. A milkproduct according to claim 38 wherein said permeate contains moleculeshaving a molecular weight less than or equal to about 2.0 kDa.
 41. Amilk product according to claim 40 wherein said permeate containsmolecules having a molecular weight less than or equal to about 2.0 kDa.42. A palatable hypoallergenic milk product comprising:(a) a permeatesubstance substantially free of allergenic protein, said permeatecontaining molecules having a molecular weight less than or equal toabout 5 kDa, and said permeate being selected from the group consistingof milk permeate and whey permeate; (b) a nutritionally effective amountof an additive selected from the group consisting of short-chainpolypeptides, amino acids, and a combination thereof; and (c) ahypoallergenic milk chocolate prepared with hypoallergenic milk.
 43. Amilk product according to claim 42 wherein said amino acids orpolypeptides, or both, are derived from at least one component selectedfrom the group consisting of casein, soy flour and lactalbumin.
 44. Amilk product according to claim 42 wherein said permeate containsmolecules having a molecular weight less than or equal to about 3.5 kDa.45. A milk product according to claim 44 wherein said permeate substanceis substantially free of protein of animal origin as determined by thesubstantial absence of protein bands upon sodium dodecyl sulfatepolyacrylamide gel electrophoresis and silver staining.
 46. A milkproduct according to claim 44 wherein said permeate contains moleculeshaving a molecular weight less than or equal to about 2.0 kDa.
 47. Amilk product according to claim 46 wherein said permeate containsmolecules having a molecular weight less than or equal to about 2.0 kDa.48. An improved in a process for obtaining palatable milk for humanconsumption from milk-producing cows which have been treated withveterinary medications, said improvement comprising the steps of:(a)obtaining a milk component from a milkproducing cow which has beentreated with veterinary medications; (b) filtering the milk componentthrough a filtration medium which will allow molecules with a molecularweight of less than or equal to about 5 kDa to pass therethrough; and(c) collecting the permeate from the filtration step, said permeatehaving a concentration of veterinary medications substantially less thanthe concentration of veterinary medications present in an unfilteredmilk component.
 49. A process according to claim 48 wherein saidpermeate substance is prepared by supplementing said milk component withpolypeptides or amino acids, or both, prior to step (b).
 50. A milkproduct according to claim 48 wherein said amino acids or polypeptides,or both, are derived from at least one component selected from the groupconsisting of casein, soy flour and lactalbumin.
 51. A process accordingto claim 48 wherein said permeate contains molecules having a molecularweight less than or equal to about 3.5 kDa.
 52. A milk product accordingto claim 51 wherein said permeate is substantially free of protein ofanimal origin as determined by the substantial absence of protein bandsupon sodium dodecyl sulfate polyacrylamide gel electrophoresis andsilver staining.
 53. A process according to claim 51 wherein saidpermeate contains molecules having a molecular weight less than or equalto about 2.0 kDa.
 54. A process according to claim 53 wherein saidpermeate contains molecules having a molecular weight less than or equalto about 1.0 kDa.
 55. A palatable hypoallergenic milk product obtainedfrom milk-producing cows which have been treated with veterinarymedications, said product comprising:(a) a permeate substancesubstantially free of allergenic protein, said permeate containingmolecules having a molecular weight less than or equal to about 5 kDa,said permeate being selected from the group consisting of milk permeateand whey permeate, and said permeate having a concentration ofveterinary medications substantially less than the concentration ofveterinary medications present in an unfiltered milk component; and (b)a nutritionally effective amount of an additive selected from the groupconsisting of short-chain polypeptides, amino acids, and a combinationthereof.
 56. A milk product according to claim 55 wherein said aminoacids or polypeptides, or both, are derived from at least one componentselected from the group consisting of casein, soy flour and lactalbumin.57. A milk product according to claim 55 wherein said permeate containsmolecules having a molecular weight less than or equal to about 3.5 kDa.58. A milk product according to claim 57 wherein said permeate issubstantially free of protein of animal origin as determined by thesubstantial absence of protein bands upon sodium dodecyl sulfatepolyacrylamide gel electrophoresis and silver staining.
 59. A milkproduct according to claim 57 wherein said permeate contains moleculeshaving a molecular weight less than or equal to about 2.0 kDa.
 60. Amilk product according to claim 59 wherein said permeate containsmolecules having a molecular weight less than or equal to about 1.0 kDa.